Discuss Rad delta T with wc. in the Plumbing Jobs | The Job-board area at PlumbersForums.net

townfanjon

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Guys , just curious, how do you work out your rad sizes when using WC , rather than a set DT of say 50
 
WC?
I work out the heat losses from room then look at Stelrad Charts to choose the rad. They do charts for 30T, 40T, 50T etc.
Does that help?

I think its the only way , as said I was just curious.
I have learnt from WC in my own house that sometimes my boiler flow temp can be lower than 45 C and it still heats the house and is no where near a DT of 40 / 50 .
I have started to leave off a “heat up”% of 1.5 because the heating is always on , would you agree ?
 
You just size as normal, the idea being that as the external temp rises from the designed low point, the required output from the heat emitter will be less to maintain the room temp. This is still met by progressively reducing the boiler flow temperature.
 
You just size as normal, the idea being that as the external temp rises from the designed low point, the required output from the heat emitter will be less to maintain the room temp. This is still met by progressively reducing the boiler flow temperature.

Cheers Chris , you have confirmed what I thought.
We bought a new house a couple of weeks ago and I am recalculating the rads . Would you agree and knock of the initial “ heat up “ calc from cold , just seems wrong putting it on .
 
Yes, if it is going to be left on for extended periods & not no/off morning & night.
Just a word of warning though for those using time control with the modern construction insulation & building mass, 10 - 15% may not be enough, DHDG recommending up to 20%
 
Christmas presents ?

Lol , me and Mrs TFJ gave up xmas presents years ago , she has everything!!! , Lol , and if the kids buy me anything apart from a bottle or two of jd I play heck with them , I rather they spend money on themselves.
 
Outdated I would say.
I have always used either Myson or Stelrad Stars, once you get use to them they are good & free. More importantly you have a record & are acting like a pro.
 
Is there a superb app out therefor heat loss, free or fee .. I don’t mind

If you want a cheap quick one , Mr combis are ok .
However I have just worked our new bedroom heat loss / rad size etc etc , I did mine long hand and know it was right ( F1 F2 etc )and then compared it to the Mr Combi , quite a bit of difference.
 
If you want a cheap quick one , Mr combis are ok .
However I have just worked our new bedroom heat loss / rad size etc etc , I did mine long hand and know it was right ( F1 F2 etc )and then compared it to the Mr Combi , quite a bit of difference.

whose was higher ?
 

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